Conventionally, as therapeutic agents for livestock comprising lactic acid bacteria, agents for livestock comprising viable bacteria, Lactobacillus acidophilus and Streptococcus faecalis (see for example, Japanese Laid-Open Patent Application No. 51-106725) are known. These agents are for promoting growth or for preventing and treating diarrhea in livestock. Further, other known agents include mixed feed for livestock comprising, in ratio to 1 g of viable-bacterial agent such as bifidobacteria, sodium chloride at 2-12 g, potassium chloride at 1-10 g, sodium bicarbonate at 2-18 g, glucose at 10-80 g, and glycine at 5-30 g. This agent is used not only for curing diarrhea or a loose-stool symptom but also for obtaining glossier-looking hair and favorable growth in livestock such as pigs and cows (see for example, Japanese Laid-Open Patent Application No. 3-61452). Moreover, a dog food for preventing and treating dog-specific infections, comprising a treated product of bifidobacteria, lactic acid bacteria, or yeast is known (see for example, Japanese Laid-Open Patent Application No. 2001-309753).
Furthermore, the followings are known as applications of bacteria belonging to genus Enterococcus that are lactic acid bacteria and of a treated product thereof: an infection preventative against candida and the like (see for example, Japanese Laid-Open Patent Application No. 05-97689); and adjuvants (see for example, Japanese Laid-Open Patent Application No. 8-99887 and Japanese Laid-Open Patent Application No. 11-92389). The known applications still further include a method for producing lactic acid bacteria having an immuno-stimulating effect wherein Enterococcus faecalis EC-12 (FERM ABP-10284) is cultured by using a medium containing corn steep liquor and casein hydrolysate (see for example, Japanese Laid-Open Patent Application No. 2004-41099); and an immunoregulatory agents comprising killed bacteria of Enterococcus faecalis AD101 strain as a principal ingredient (see Japanese Laid-Open Patent Application No. 2001-48796) However, it was not known that Enterococcus faecalis EC-12 (FERM ABP-10284) has an extremely superior suppressive effect against diarrhea in livestock and poultry.
“Diarrhea” basically represents increased moisture content in feces, and is classified broadly according to the developmental mechanism of diarrhea into three groups: osmotic diarrhea; secretory diarrhea; and a diarrhea caused by abnormal transit time. Osmotic diarrhea is caused by increased osmotic pressure in the intestinal tract, which is attributed to substances that are not absorbed by the intestinal tract. Secretory diarrhea is caused by bacterial toxin, hormone, chemical substances and the like that accelerate secretion of water and electrolyte in the intestinal tract. Secretory diarrhea is wide in variety. Among secretory diarrheas, there are two types that are caused by bacteria: a type in which diarrhea is caused by bacterial toxin, and mucosal damage is not involved (for example, a certain kind of Escherichia colil ); and the other type in which diarrhea is caused by mucosal damage induced by bacteria that have invaded into cells (for example, Salmonella). Fatty diarrhea and bile acid diarrhea based on malabsorption of fat or bile acid, are also a type of secretory diarrhea. In addition, diarrhea also occurs in inflammatory intestinal diseases as a result of increased permeability of intestinal wall. Among diarrheas with abnormal transit time in intestines, those attributed to lowering of speed include intestinal stenosis and blind loop syndrome such as diverticulosis. These diarrheas are caused by abnormal bacterial growth. Meanwhile, diarrheas attributed to enhancement of speed include irritable bowel syndrome and hyperthyroidism. These diarrheas are caused by increased intestinal motility.
In growing pigs, some weaning piglets and sows may develop dyspeptic diarrhea. Feeds for pigs being grown contain about 40-80% cereal which primarily comprises corns. Although starch is digested and absorbed in a pig's small intestines, the secretion of digestive enzyme and gastric acid is insufficient if a large amount of digesta comes at a time into the small intestines or in the case of a piglet around the weaning period or of a breast-feeding sow. In these cases, the starch cannot be completely absorbed and digested by the small intestines. Thus, the starch may come into the large intestines. Some bacteria of genus Streptococcus, a kind of lactic acid bacteria in the large intestines, quickly degrade starch and rapidly produce lactic acid. Some of such bacteria even multiply themselves. Thus, lactic acid abruptly increases in the large intestines. Consequently, an abrupt decrease in pH occurs. Such decrease kills or weakens other bacteria, resulting in abnormal large-intestinal flora. When such abnormal flora is generated, diarrhea occurs. At this moment, lactic acid as well as succinic acid, whose property is similar to that of lactic acid, are abundantly detected in the diarrheal stool.
As just described, diarrhea often occurs when an abnormal large-intestinal flora has been developed for various reasons. Further, mass accumulation of lactic acid adversely affects large-intestinal tissues. It not only damages the large-intestinal tissues and thus decreases thickness of the large intestines but also incurs possible secondary damage in which the large intestines become more susceptible to a pathogenic invasion as a result. Consequently, the large intestines become more susceptible to diarrhea-inducing pathogenic bacteria, pathogenic viruses and pathogenic protozoa, such as Escherichia coli, Clostridium perfringens, Brychispira hyodysenteriae, Lowsonia intracellaris, Salmonella sp., rotavirus and coccidium.
Meanwhile, colibacillosis in pigs is broadly classified according to causative bacteria and the developmental mechanisms into Escherichia coli diarrhea, Escherichia coli enterotoxemia, and Escherichia coli septicemia. Diarrhea and septicemia frequently occur during the neonatal period. The principal cause of diarrhea is an infection of enterotoxigenic Escherichia coli which belongs to a specific serotype. Enterotoxemia is developed during the weaning period (4-12weeks old). The causative bacteria of Enterotoxemia are collectively referred to as Enterotoxemic Escherichia coli (ETEEC). ETEEC colonizes in the small intestines and produces toxin as a result. The absorbed toxin impairs the target tissue and thereby induces Toxemia. Edema disease (ED) is a typical Escherichia coli enterotoxemia. The causative bacteria of Edema disease (ED) belong to a specific serotype. These bacteria fall into the category of verotoxin-producing Escherichia coli (VTEC). Edema disease (ED) occurs sporadically in many cases, but at times, small-scale epidemics are provoked. On rare occasions, Edema disease attacks 2-3 week old suckling piglets or even adult pigs. Adult pigs follow more chronic courses than weaning piglets. Characteristically, Edema disease abruptly occurs in some pigs in the herd and ends after a short period of time (4-15 days). However, it may reappear repeatedly in the same farm. Although the attack rate of the disease is 10-40%, the death rate is as high as 50-90%. In many cases, Edema disease (ED) is caused by an infection with single-serotype bacteria. Meanwhile, it is sometimes caused by an infection with plural types of bacteria. The serotypes (0139, 0141) of causative bacteria of Edema disease (ED) are common in all countries. Experimentally, Edema disease is developed by orally administering 105×0139 bacteria for 3 days. It is known that a propagation usually occur via feces, aerosol or affected feed. It is also known that affected farms suffer from contamination over a long period of time (“Rinsho-to-Biseibutsu” Vol. 23, 843-849, 1996).
Of all livestock, pigs are recently in much demand particularly as edible meat. Among such pigs, piglets at the suckling period and around the weaning period or breast-feeding sows me attacked by Edema disease. Edema disease involves diarrhea which is caused by pathogenic Escherichia coli. Edema disease is often observed in weaned piglets. In an affected farm, 10-40% piglets are said to develop this disease.
Citation or identification of any document in this application is not an admission that such document is available as prior art to the present invention.